1. Field of the Invention
The present invention is directed to an assembly machine for joining the edges of a pair of sheets of plastic material of large dimension.
2. Description of Related Art
The assembly, edge to edge, of two sheets of plastic material of large dimension is realized by two operators placed at the entrance and exit of an assembly machine consisting of a horizontal platform containing a fixed electrode on top of which the first operator places the two edges of the two sheets to be assembled after which, and after having verified that the two edges are placed correctly on the fixed electrode, the operator orders the descent of a mobile electrode in vertical movement on top of the aforementioned edges for the purpose of creating their contact and joining one to the other. After the joinder operation is complete the second operator on the one hand pulls the two sheets away in a manner which permits the first operator to place a new section of edges to be joined, and on the other hand positions material in the center of the fixed electrode to assist the first operator in placing the two edges one on top of the other on the fixed electrode.
However, the use of these machines carries with it a higher assembly cost as a result of the presence of the two operators. On the other hand, the handling operations of the sheets are burdensome to the operator at the exit of the machine who has to pull with force the two sheets of large dimension on each of the assembled edges to remove them from the joinder position. Furthermore, it sometimes happens that the operator, who maintains the two edges on the fixed electrode during their merger, positions by mistake his fingers between the two electrodes, which fingers then are squeezed between the latter.